“He was left for dead in his own home, a place where he should feel safest. There is no way of knowing when he would have been discovered.

“Had it not been for a member of the public raising the alarm, I believe that Mr Gouldstone would have succumbed to his injuries.

“My investigation team has been working relentlessly to trace the individuals behind this horrific attack.”

The widowed pensioner worked on phone lines in Italy during the Second World War, and later joined the Post Office.

He has been retired for almost 40 years, according to his son, Simon Gouldstone.

The former civil servant, 67 – who found his father after being alerted to a possible disturbance at the property by neighbours – said: “As a member of the family I’m shocked, as a member of the human race I’m lost for words at man’s inhumanity to man I’m afraid.

“I don’t know how they can live with themselves. The sooner they’re locked up the better.”

As well as being assaulted, Mr Gouldstone – who has rarely been seen outside since his wife Joan died several years ago – also had a number of items stolen, including a black 26in Panasonic TV.